Western Jin Dynasty
The Western Jin Dynasty unified China briefly during the Six Dynasties Period.
It conquered the State of Cao Wei in 265, and then unified China proper in 280 by conquering the state of Eastern Wu.
The Western Jin fell to a series of civil wars beginning in 304 and ending with the final end of the dynasty in 317. The Western Jin capital of Luoyang fell to Xiongnu attackers in 311, and Chang'an in 316. From that time forward, China was disunited for nearly three hundred years, until its reunification under the Sui Dynasty in 589.
References
- Conrad Schirokauer, et al, A Brief History of Chinese and Japanese Civilizations, Fourth Edition, Cengage Learning (2012), 82.